Honing tool for bores of small diameters



1954 D. T. PEDEN HONING TOOL FOR BORES OF SMALL DIAMETERS Filed April 22, 1952 United States Patent HONING TOOL FOR BORES OF SMALL DIAMETERS Douglas T. Peden, Ann Arbor, Mich., assignor to Micromatic Hone Corporation, Detroit, Mich., a corporation of Michigan Application April 22, 1952, Serial No. 283,603

9 Claims. (Cl. 51184.1)

This invention relates to honing tools, and more particularly to devices adapted for honing the internal surfaces of relatively small articles.

The job of finishing the internal surfaces of extremely small parts such as are used in watches and similar mechanisms presents several important problems, especially where the finishing operation is to be done by a honing stone which is simultaneously reciprocated and rotated against the internal surface. One problem is that of gaining access to a suffiicent portion of the surface to allow finishing of the entire length of surface in a single operation. In addition, it is necessary to provide means for continuously feeding the abrasive stone radially outwardly as the internal diameter increases and as the working surface of the stone disintegrates during the honing.

It is an object of the present invention to provide a novel and improved honing tool especially adapted for small diameter bores, which overcomes these problems by allowing the simultaneous finishing of the entire length of surface, and by providing means for feeding the abrasive stone radially outwardly during the operation.

It is another object to provide an improved honing tool of the above character which is adapted for mounting on conventional types of honing machines which impart reciprocation and rotation to the tool and which have actuating means for the radial stone adjusting mechanism of the tool.

It is a further object to provide an improved honing tool as described above, in which an elongated abrasive stone is mounted, the tool head carrying the stone in angular relation with the work axis, so that longitudinal feeding of the stone will move its working surface radially outwardly with relation to the work axis.

It is another object to provide a honing tool of the above character which is especially adapted for operation with gauging means for measuring the bore diameter and automatically stopping the operation when the proper diameter is reached.

Other objects, features, and advantages of the present invention will become apparent from the subsequent description, taken in conjunction with the accompanying drawings.

In the drawings:

Figure 1 is an elevational view in cross section of a preferred embodiment of the invention showing the abrasive stone in operative engagement with a work- 1ece; p Fig. 2 is a fragmentary cross-sectional view taken along the line 2--2 of Fig. 1 and showing the guide shoe for the stone;

Fig. 3 is a fragmentary cross-sectional view taken along the line 3--3 of Fig. 1 and showing the cooperation of the feed plunger and guide;

Fig. 4 is an elevational view of the entire tool showing its means of connection with a conventional honing machine; and

Fig. 5 is a view of a fixture for holding the work in proper position for the honing operation.

The invention comprises a hone body generally indicated at 11 adapted to be mounted on any of the conventional honing machines which impart simultaneous reciprocating and rotating motion to the body. Such a machine is shown for example in my Patent No. 2,350,527 issued June 6, 1944, and the details of the machine forming no part of the present invention, they need not be described in detail. The hone body is of generally cylindrical shape but has a tapered nose portion 12 with a "ice flat end surface 13 from which an abrasive stone 14 extends. This stone 14 is of solid cylindrical shape and in particular has a radial back face 15 and an oblique working face 16 which engages the internal surface 17 of a work piece 18 such as an inner bearing race surface 16 thus being of convex shape. The abrasive stone 14 is disposed at an angle relative to the longitudinal axis of the hone body and is supported by a' guide tube 19 which is secured in the nose portion of the body and extends outwardly therefrom. The exact angularity of this tube relative to the body axis is not critical and this angle may be varied to suit the particular requirements of the job. For example, if it is desired to have very small diameters or to have a more sensitive radial adjustment, the angularity of the stone may be relatively small. The outer end of tube 19 is provided with an oblique end surface 21 which during operation will be a relieved surface relative to the working surface 16 of the stone. The abrasive stone, which is a metal bonded diamond abrasive or other conventional honing substance may be surrounded by a plastic sheath 22 for protective purposes.

Means are provided for urging the stone 14 in a longitudinal direction through tube 19 during the operation in order to move surface 16 radially outwardly. This means preferably comprises a feed plunger generally indicated at 23 having a stem portion 24 in engagement with the back face 15 of the stone, and a combined guide and actuating head 25 rearwardly of the stem portion. Head 25 is slidable within a bore 26 in the hone body, this bore being disposed immediately behind the guide tube 19 and coaxial therewith. The hone body is further provided with a radial slot 27 which is contiguous with the bore 26 and within which slides a feed plunger guide 28. This guide is fixedly secured to the end of a feed rod 29 which is adapted to be attached to the adjusting head (not shown) of the honing machine by an attaching head 31, seen in Fig. 4. As is shown in detail in the aforesaid patent, the attaching head, which is secured to the feed rod by a pin 32, is adapted to be locked to the adjusting head by a plurality of ball elements disposed in an annular groove 33.

During operation the feed rod is of course continuously fed toward the work in order to adjust the abrasive stone. For this purpose, feed plunger guide 28 is provided with a radial edge 34 which fits slidably in a slot 35 at the end of the feed plunger actuating head 25. It will thus be seen that axial movement of the feed rod 29 Within bore 30 toward the stone 14 will cause the plunger 24 to force the stone 14 in a longitudinal direction, moving its working surface 16 radially outwardly. It will be observed that the retractive movement is limited by the stop surface 36, as illustrated in Fig. 1, which limits the rearward movement of the feed plunger guide, and that the forward movement is limited by the end 37 of bore 30 when engaged by the inclined forward edge 38 of the plunger guide. It is thus seen that a substantial length of the abrasive stone can be employed before replacement becomes necessary.

Means are provided for backing up the Working end of stone 14 as the operation progresses in order to insure a uniform operation. This means preferably comprises a hardened steel guide shoe 39 of tapered shape which is secured to the end of tube 19 opposite the opening from which the stone protrudes. The shoe 39 has a work engaging surface 41 of convex shape which will hold the tube against any unwanted cantilever movement due to the pressure on stone 14, and the shoe will thus provide a firm backing for the stone working surface.

As stated previously, the hone body 11 is adapted to be secured to a conventional honing machine, and for this purpose a radial adapting shoulder 42 may be provided which has one or more dowel holes 43 for attachment to the machine. As seen in Figure 4, the hone body may be further provided with an attaching sleeve 44 extending rearwardly from shoulder 42 and adapted to be held by the machine. A clearance bore 45 for assembly purposes may also be provided in the hone body, this opening extending coaxially with the guide bore 26.

The operation of the machine is preferably such that the working surface 16 of the abrasive stone will extend a substantial axial distance beyond the workpiece at the end of each stroke, and the device is adapted to be used in conjunction with automatic gauging means such as are described in the patent to Connor et al., No. 2,308,356 issued January 12, 1943. For this purpose the work is preferably held by a clamping fixture generally indicated at 46 which is mounted for bodily pivotal movement on a pin 47 so as to swing against a locating stop 48. The clamping fixture is provided with split jaws 49 which clamp the work in a space 51 between front and rear walls 52 and 53, a clamping screw 54 being provided for closing the clamp jaws. The rear wall 53 of the fixture is provided with a clearance aperture 55 for allowing the reciprocating movement of the tool to take place. Front wall 52 may support a gauge means in the form of a rotatable cam 56 mounted in an aperture 57 of wall 52. A hardened steel gauge ring 58 held by cam 56 is disposed in the path of the reciprocating work surface 16 of the stone, so that when the proper internal diameter is reached the surface 16 will engage the gauge ring to rotate cam 56. As described in more detail in the aforesaid Connor patent, this rotation will cause actuation of switching means (not shown) to stop the honing operation.

The operation of the entire honing tool will be apparent from the foregoing description. After the workpiece 18 is clamped in place between jaws 49 and the clamping fixture 46 is moved against stop 48, the stone supporting tube 19 together with stone 14 will be fed into the Work bore in the direction of the bore axis, surfaces 16 and 41 of the stone and the guide shoe 39 respectively engaging opposite sides of the bore surface. The honing machine is then started so as to impart simultaneous reciprocating and rotating motion to the hone body 11. Due to the angular disposition of the stone 14 with respect to the work axis, this motion will cause the relatively broad working surface 16 to abrade the bore surface in a sinuous manner to hone the entire surface. Simultaneously with this action the feed rod 29 will be slowly fed inwardly and the feed plunger guide 28 will move within slot 27 against the guide portion of the feed plunger 23. This will urge the reduced portion 24 of the plunger against the cylindrical stone, and due to the angular disposition of the stone its longitudinal movement will force the Working face 16 thereof outwardly so as to increase its radial distance from the bore axis. When the proper bore diameter has been reached the gauge cam 56 will be automatically actuated to stop the operation.

It will be observed that due to the novel angular arrangement of the abrasive stone within hone body 11 it is possible to obtain both the honing motion and the feeding motion of the stone with a relatively simple arrangement of parts. The unit is capable of high sensitivity in adjustment by virtue of the angular relationship of the stone and its feed rod 29. It will also be noted that this arrangement allows a maximum working surface of the abrasive stone to be constantly in action and also permits a maximum amount of the stone to be used before replacement becomes necessary. It is thus seen that the arrangement permits the honing of extremely small bore diameters in a highly efficient manner and with maximum accuracy.

While it will be apparent that the preferred embodiment of the invention herein disclosed is well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

1. In a honing tool, a hone body adapted to be rotated about an axis, an abrasive stone encompassed by said hone body with one end extending outwardly therefrom, said stone being disposed angularly with respect to the hone body axis and having a working surface at said outer end thereof parallel to the axis body, a guide shoe extending from the hone body for holding said work surface against the work, and actuating means for feeding said stone end outwardly from the body at an angle to the body axis, said means comprising a feed member within said hone body and engageable with the inner end of said abrasive stone.

2. A honing tool comprising a hone body adapted for rotation about a work axis, a tubular stone supporting member extending outwardly from one end of said hone body, the axis of said member being angularly displaced from said hone body axis, an abrasive stone movably disposed within said supporting member and adapted to extend therefrom and having a working surface disposed parallel to the hone body axis, and actuating means within said hone body and engageable with said stone for moving the stone longitudinally, whereby the working surface of said stone is moved radially with respect to the hone body axis.

3. A honing tool comprising a hone body adapted for rotation, an abrasive stone of elongated shape encompassed by said hone body and disposed in angular relation to the body axis, one end of said stone extending from said body and having an oblique working surface parallel to the body axis, projecting means on said hone body for backing up said extending stone end and holding said working surface in engagement with the work during rotation of said hone body, and adjusting means for feeding the stone along its longitudinal axis, said adjusting means comprising a member mounted within said hone body for movement in the same direction as said stone.

4. A tool for honing an internal surface comprising a hone body adapted for rotation about an axis, an elongated abrasive stone extending from one end of said hone body and disposed angularly with respect to the body axis, adjusting means for feeding said stone outwardly along its axis, said adjusting means comprising a plunger slidably mounted within the hone body, and a feed guide within said hone body and movable in the direction of the hone body axis, said feed guide being engageable with said plunger to cause movement of the latter in the direction of the stone axis while relative lateral movement occurs between the plunger and guide.

5. A tool for honing internal surfaces comprising a hone body adapted to be rotated, a stone-supporting tube extending from said hone body, the axis of said tube being angularly displaced relative to the hone body axis, an elongated abrasive stone supported in said tube and having a working surface extending outwardly from the ube, a feed plunger within the hone body disposed in alignment with the stone and engageable therewith, and means mounted within the body and movable parallel to the axis thereof for engaging said feed plunger and moving the latter in the direction of the stone axis while lateral movement occurs between said means and plunger.

6. A tool for honing internal surfaces comprising a rotatable hone body having an angular bore and a slot communicating therewith, a stone-supporting tube extending from said hone body bore, an abrasive stone within said tube and having a working surface engageable with the work and disposed parallel to the axis of the hone body, a feed plunger slidable in said bore and engageable with the inner end of said stone, and a feed plunger guide within the slot in the hone body in which it is slidable in a direction parallel to said hone body axis, said guide being engageable with said plunger to move said stone longitudinally while a relative lateral movement occurs between the plunger and guide.

7. A tool for honing internal surfaces comprising a rotatable hone body, a stone-supporting tube extending angularly from said hone body, an abrasive stone within said tube and having a working surface extending therefrom, a feed plunger within said hone body and engageable with the inner end of said stone, a guide in said hone body movable therein into engagement with said feed plunger, and a feed rod within said body supporting said guide and for movement parallel to the axis of said hone body, whereby axial movement of said feed rod will cause longitudinal movement of the stone and the radial movement of the working surface.

8. A tool for honing internal diameters comprising a hone body of elongated shape and rotatable about the work axis, said hone body having an oblique bore extending partially therethrough, a stone-supporting tube communicating with said bore and extending from one end of said hone body, an elongated abrasive stone supported by said tube, the outer end of said tube and stone being disposed at an acute angle thereto and provided with an arcuate surface struck from the body axis in one position of the end, a feed plunger within said bore and engageable with the inner end of said stone, and a feed plunger guide engageable with the feed plunger. said guide comprising a member movable in the direction of the hone body axis.

9. A stone for a honing tool comprising a cylindrical abrasive element made of bonded abrasive material, and a cylindrical casing encompassing the cylindrical wall of said stone and secured thereto, one end of said casing Number Name Date and stone being disposed at an acute angle with the 5 431,713 Whaley July 8, axis thereof and having the shape of a section of a Wall of 1,756,014 Streby Apr. 29, a cylinder, said casing being constructed of a material 2,001,122 Brickner May 14, which wears at a rate at least as fast as said abrasive 2,419,660 Satterthwaite Apr. 29, element 10 FOREIGN PATENTS Number Country Date 578,652 Great Britain July 5, 1946 6 References Cited in the file of this patent UNITED STATES PATENTS 

